WW and 3/8 ID tubing?

I am going to be building a water chiller this summer out of an A/C unit and plan to get liquid temps around -25c.

Now since I have to insulate the tubing I would like to run 3/8 ID tubing on a WW instead of 1/2 ID tubing. I am doing this just so the lines are manageable inside my case.My question is how badly will running 3/8 ID tubing hurt the performance of this block? If it is going to take a significant loss I might have to think about a swiftech 6000 block since they have similar performance.

The reason I do not just get a swiftech block is the wacky socket A mounting and I think it will be MUCH easier to insulate the WW the way I have it planned vrs the swiftech block. However if I am gonna lose a lot of performance I will consider a swiftech block.

Anyway give me your thoughts if you want .

i'm not sure about that but there is something else.
wiht temps as low as -25c my guess is that u'll be using antifreeze/coolant at a high ratio cuz water will freeze. With such a viscious liquid, this will be a noticible pressure drop. i would consider a non restrictive block instead..

Hrmmm ya I never thought about it like that. The mixture will proboly be denatured alcohol/antifreeze but its still gonna be pretty viscous.

What would a good low restriction block be? I would like to use a retention system similar to the WW since I know it will be easier to mount all my insulation that way (to me thats more than half the battle).

the maze 4 and becooling slitedge have the lowest, tested pressure drop according the the overclocker's review.
maze 4 is cheaper though, so i'd go with that

Yah I think I am gonna go with a maze4. It has the similar mounting to the WW so my neoprene will be easy to mount. The increase in flow should help make up for the poorer performing block.

d-tek tc4 would also be a good choice, and you can get then real cheap ATM.